Tubular heat-exchanger



A Wu

A. HUET TUBULAR HEAT-EXCHANGER Filed April 22, 1957 IN VEN TOR.

KNDRE HUET ATTORNEY .UnitedStates Patent ()fifice 2,905,447 Patented Sept; 22, 1959 HEAT-EXCHAN GER Andr' Huet, France Application April 22, 1957, Serial No. 654,304 Claimspiiority, application France May 4, 1956 '3 Claims. c1. 257-26214) Tubular heat-exchangers are known, in which pipes are used provided withlongitudinal fins. In: accordance with the present invention, in order to create variations of direction, speed and pressure in the fluid circulating between the pipes, it is proposed to wave the fins of those pipes.

In a first realisation, the pipe itself and its fins are waved along the axis.

Or, only certain fins of the same pipe can be waved in the longitudinal direction, the others remaining in the diametral planes. In another form, leaving the fins of the pipes in diametral planes, waved metal-sheets are placed between the fins of a same tube or between the fins of adjacent pipes, in the direction of the flow of the fluid.

Moreover, on solid cores provided inside the pipe, are made small projections in the form of ribs which find support on the inner surface of the pipe. These small ribs, which can be in a single piece with the solid core, can themselves be waved in the longitudinal direction, so as to finally obtain the same favorable effects for exchange of heat in the fluid circulating inside the pipes.

The description now following, in respect of the annexed drawings, given by way of examples, will make it easier to understand how the invention can be realised.

Fig. 1 shows a pipe with longitudinal fins, waved according to its longitudinal axis.

Fig. 2 shows, in perspective, a tube with certain of its fins waved longitudinally.

Fig. 2a is a perspective view of a portion of a tube having fins in accordance with another embodiment of the invention.

Fig. 3 shows, as section, a part of a heat exchanger with pipes, according to the invention, and waved metal sheets set between the fins.

Fig. 4 shows, in perspective, one of the solid cores used on the inside of Fig. 3 of the pipes of the exchanger.

As will be seen on Fig. 1, the pipe I as used, is provided with longitudinal outer fins and the whole of the pipe is waved along its axis, as it has been shown in perspective. In that way, assembling of the pipes with parallel axes, is such that the intervals included between the pipes, subject the fluid circulating on the outside of those pipes, to variations of direction.

Instead of waving the pipe and the fins as a whole around its axis, it is possible, as shown in Fig. 2, to wave only certain of the pipe fins. In Fig. 2, the pipe r, possessing six longitudinal fins diametrically on its outer surface is such that one fin out of two, like the fin s for instance, is waved in the longitudinal direction of the axis of the pipe, in an asymmetric manner for preference, that is to say that a long branch of the waved fin is followed by a shorter branch, more inclined. The other fins 1 remain flat and diametrical. In that way, in the channels formed between the fins, imbricated or not, of the pipes associated for constitution of the exchanger and in which the outer fluid circulates, takes 2 place section and direction variations, the effect of which is to improve the heat exchange.

Instead of waving the fins such as s there can be welded or fixed by welding-points, on the pipe 1' itself, between the fins left fiat, strips of corrugated sheet-metal u as shown in Fig. 2a. Those sheets can afterwards he fixed by a few welding-points on their other edge, either to arib of another pipe associated with the first, to constitute the heat-exchanger, or on the wall: of the pipeitself. That edge, again, can remain free. I

Orr-Fig. 3 is shown assectioman arrangement in which the pipes r, with six fiat fins on their outer surface, are arranged in'quincunx', the ends of the fins coming very close one to the other and metal-sheets v are welded fin to fin as it is to be seen in the drawing, so as to' make compartments of the intervals offered to the flow of the outer fluid and, in those gaps, to obtain the desired direction and section variations.

It is of course understood that those sheets v contribute in modifying the flow conditions of the outer fluid.

The metal-sheets v could be also welded as indicated in the foregoing, from the wall of a pipe to the wall of another pipe. The choice of the arrangement of the v sheets depends on the arrangement adopted for assembling the pipes, according to whether the fins are imbricated more or less one in the other and the v sheets are fitted in such a way that the canals existing between fins are suitably subdivided.

In Fig. 3, the solid core e that is fitted into the pipes, possesses small rib or fins w on its outer surface. Those small ribs w can, for preference, be waved in the way seen at w (Fig. 4) and, in the canals produced between the core 2 and the pipe r for flow of the inner fluid, cause directional variations, and at the same time allow centering of the core 2 on the inside of the pipe r.

What I claim is:

1. A heat exchanger comprising a plurality of tubes disposed in substantially parallel relationship, each tube being provided with a plurality of radially-extending fins, at least some of said fins of each tube being of undulate form longitudinally of said tube, and at least some of said fins of each tube being rectilinear longitudinally of said tube, whereby each tube has both rectilinear and undulated fins, and said fins being relatively disposed in such manner that each rectilinear fin is disposed adjacent an undulated fin to define a longitudinal channel of varying cross-section between said rectilinear fin and said adjacent undulated fin.

2. A heat exchanger comprising a plurality of tubes disposed in substantially parallel relationship, each tube being provided with a plurality of adjacent pairs of radially-extending fins, one fin of each pair being of undulate form longitudinally of said tube and the other fin of each pair being rectilinear longitudinally of said tube, and said fins being relatively disposed in such manner that each rectilinear fin is disposed adjacent an undulated fin to define a longitudinal channel of varying cross-section between said rectilinear fin and said adjacent undulated fin.

3. A heat exchanger comprising a plurality of tubes disposed in substantially parallel relationship, each tube being provided with a plurality of radially-extending fins, at least some of said fins of each tube being of undulate form longitudinally of said tube, and at least some of said fins of each tube being rectilinear longitudinally of said tube, whereby each tube has both rectilinear and undulated fins, and said fins being relatively disposed in such manner that each rectilinear fin is disposed adjacent an undulated fin to define a longitudinal channel of varying cross-section between said rectilinear fin and said adjacent undulated fin, some of said fins on each tube being integral with the associated tube and the other fins on each tube being secure thereto.

4. A heat exchanger comprising a plurality of tubes disposed in substantially parallel relationship, each tube being provided with a plurality of radially-extending fins, at least some of said fins of each tube being of undulate form longitudinally of said tube, and at least some of said fins of each tube being rectilinear longitudinally of said tube, whereby each tube has both rectilinear and undulated fins, and said fins being relatively disposed in such manner that each rectilinear fin is disposed adjacent an undulated fin to define a longitudinal channel of varying cross-section between said rectilinear fin and said adjacent undulated fin, and longitudinally-extending strips interconnecting adjacent tubes of said plurality of tubes.

5. A heat exchanger comprising a plurality of tubes disposed in substantially parallel relationship, each tube being provided with a plurality of radially-extending fins, at least some of said fins of each tube being of undulate References Cited in the file of this patent UNITED STATES PATENTS 2,275,829 Tull Mar. 10, 1942 2,804,284 Otten Aug. 27, 1957 FOREIGN PATENTS 644,442 Great Britain Oct. 11, 1950 

